Alpena weekly argus. [volume] (Alpena, Mich.) 1871-1893, 1887-07-27

then TO the wet machine, and is wound In
rolls like carpeting ready for the market
II is sold to the paper makers, who use il
as n substitute for rags in all grades OF pa
per.
In making the bisulphite solution three
towers are used. These towers are built Of
three inch Norway slaves, are five feet in
diameter and los feet high. AT the bottom
there is heavy wooden grating, and from
here to the top of each tower is filled with
porous limestone. At the tops of the tow
ers are tanks filled with water.
A spray of water drizeles over the stones
while from under the wooden grating risel
a column of sulphur gas or sulphurous acid
which is obtained by burning pure sulphur
in furnace at the base althe towers. Thi'
gas enters the towers, is condensed by the
water coming down, and dissolves the lime
stone. The limestone is not removed, but
as il settles down is renewed from the toI
Of the towers about every week. Once a
month the scrabble" is cleaned out. This
solution, the result of the operation in the
tower, is gathered in tank AT the bottom
and forced by means of air pressure into
receivers, which stand high enough to al
low the flow of liquor into the digesters
This liquor is readily secured of strength
of from six TO ten degrees Beaume.
The digesters or boilers are built from
three-quarter inch iron in the shell, with
heads of inch iron, the heads bullying about
n foot. They rest on saddles to allow foi
expansion, and are set on heavy iron grid
ers about a foot from the ground hoors
After being placed in position the boiler.
are painted inside with sticky paint made
from pitch and coal tar, and are then lined
with lead foil of the thickness of paper
This foil is laid all over the interior sur
faces double and is simply a precautionary
measure. Then the insides are laid with
acid-proof brick, which is imported from
Europe. These brick are tongued and
grooved and arc laid in a special Portland
cement, the second course being laid edge
wise. The brickwork makes lining offs
inches. These brick are not only acid
proof, but they are made so that they ex-
pand and contract with the temperature OF
the boilers. The heating pipes in the boil
ers are made of composition Of lead and
anthony and stand pressure of l2O
pounds, although in work pressure of six
ty-eight pounds is used. These pipes last
four or five years, and then have to be re-
placed at cost of $500. Valves are made
of sort Of phosphor-bronze, but are lined
with lead and anthony, as are also the
stuffing-boxes, etc.
The mill is also equipped with three
steam-boilers and $50 horsepower steam
engine, an electric light plant, and turns
out from FIVE to six tons per day, which
product will be doubled when the two adj
ditional digesters are put in.
The main point in the operation is that
there must be surplus of lime in solution.
Otherwise as soon as the cooking comes to an
end and the lime in solution Is exhausted,
it is necessary to blow off the liquid or the
wood will be turned black. 1t is ofthe ut
most importance to have this surplus of
lime in order TO produce pure white fibre.
With the liquor at six degrees Beaume the
boilers can be filled and the liquor is not
exhausted when the timber is turned into
fibre. Pine, spruce and hemlock are the
woods used. Poplar Is not quite so strong,
but very white and preferred for finer pa
per to cedar Beech and maple dissolve as
easily, but do not have the strength fpine.
One and a quarter cords of wood make a
ton of sulphite fibre, dry weight, and the
fibre from twenty-five or thirty cords of
wood-the charge of boiler-doeS not
contain an unreduced piece as large as a
hickory nut.